The present invention relates generally to so-called safety tires, and more specifically to a safety tube assembly for pneumtic tires having run-flat capabilities.
Already, there are known tubeless pneumatic tires which are characterized as being puncture-proof and which when punctured can run at certain speeds for certain periods of time.
Such tires are capable of running either in an entirely flat condition or in a substantially deflated state when they are locally punctured, perforated, or pierced.
However, these tires are uncomfortable and wear out at an excessive rate, when they are used in a flat or substantially flat condition.
Moreover, such tires have a drawback in that they are extremely heavy and expensive.
A further drawback exists in that the above-mentioned tires require special construction and configuration and must be mounted on a vehicular wheel rim of corresponding construction. As a result, the combination of such a tire and its vehicular wheel rim is extremely costly and complicated.
Other tubless pneumatic tires employ the addition of extra reinforcing layers and spacer projections integral with or attached to the internal surface of the carcass or external surface of the tube to ensure that these two members remain spaced from one another when the air chamber between them deflates.
However, such tires have two basic difficulties in that firstly, the provision, usually in rubber, of spacer projections or layers involves the addition of extra mass with consequent high speed performance penalty, and secondly, the projections or layers involve considerable modification and complication of the carcass and tube construction with consequent price increase.
Accordingly, the known pneumatic tubless tires may become punctured from sharp-tipped objects lying on the roadway, whereby the sudden loss of air causes instability of the vehicle. If the vehicle is running at high speed, the instability of the vehicle subjects the vehicle occupants to great danger.
Heretofore, the construction of the pneumatic tires have been reinforced to avoid the danger of a sudden blowout. However, it has been noted that the cause of many fatal accidents is due nevertheless to the failure of such reinforced tires themselves.